The invention relates to an electrical apparatus, more particularly to an electrical apparatus having a cover member that is adapted to provide electromagnetic interference shielding to an electronic component.
The design of notebook computers has a current trend toward compactness. In order to ensure enhanced performance for a notebook computer, an expandsion slot for additional memory modules can be found in the notebook computer. Memory modules are getting smaller in size. At present, the specifications of 144-pin and 0.8-mm pin distance for a SODIMM memory are now being replaced by 200-pin and 0.6-mm pin distance. Therefore, it is important to provide electromagnetic interference shielding to a memory module especially during high-frequency operation.
FIG. 1 illustrates a conventional notebook computer that includes housing 1 and a cover member 2. The housing 1 has a circuit board 12 received therein. The circuit board 12 is mounted removably with a memory module 13 thereon via a slot 121 that is mounted on the circuit board 12. With further reference to FIG. 2, the circuit board 12 has a set of ground contacts 122, such as solder pads, that are disposed around the slot 121 on the circuit board 12. Each of the ground contacts 122 is provided with a resilient hook-shaped conductive piece 123 that is soldered thereon. The housing 1 further has a wall portion 10 formed with an access opening 11 to permit access to the memory module 13 on the circuit board 12. The wall portion 10 has an inner surface with a conductive first grounding plate 111 mounted thereon. The first grounding plate 111 is formed with a flange 112 that extends radially and inwardly relative to the access opening 11. The flange 112 contacts directly the conductive piece 123 so as to establish electrical contact with the ground contacts 122. The cover member 2 includes a dielectric cover plate 20 mounted detachably on the housing 1 so as to cover the access opening 11. The cover plate 20 has an inner surface with a conductive second grounding plate 21 mounted thereon. The second grounding plate 21 is provided with a set of contacts 211 that extend through the access opening 11 so as to establish electrical contact with the flange 112 of the first grounding plate 111 when the cover member 2 covers the access opening 11. As such, the contacts 211 of the second grounding plate 21 establish electrical contact with the ground contacts 122 via the flange 112 of the first grounding plate 111 and the conductive pieces 123. Therefore, the ground contacts 122, the flange 112 and the contacts 211 can cooperate to provide electromagnetic interference shielding to the memory module 13.
The following are some of the drawbacks of the aforesaid conventional notebook computer:
1. Due to the use of the conductive pieces 123 that are soldered to the ground contacts 122, the requisite material and additional soldering process for the conductive pieces 123 result in higher costs.
2. Since the conductive pieces 123 are hook-shaped, the conductive pieces 123 are easily deformed during assembly such that the conductive pieces 123 cannot provide good electrical contact with the flange 112 of the first grounding plate 111, thereby resulting in inferior electromagnetic interference shielding.
Therefore, the object of the present invention is to provide an electrical apparatus having a cover member that is adapted to provide superior electromagnetic interference shielding to an electronic component without incurring a substantial increase in costs.
According to the present invention, an electrical apparatus comprises:
a housing having a circuit board received therein, the circuit board being adapted to be mounted removably with an electronic component thereon, and having a set of ground contacts that are disposed around the electronic component on the circuit board, the housing further having a wall portion formed with an access opening to permit access to the electronic component on the circuit board, the wall portion having an inner surface with a conductive first grounding plate mounted thereon, the first grounding plate being formed with a flange that extends radially and inwardly relative to the access opening; and
a cover member including a dielectric cover plate mounted detachably on the housing so as to cover the access opening, the cover plate having an inner surface with a conductive second grounding plate mounted thereon, the second grounding plate being provided with a set of first contacts that extend through the access opening so as to establish electrical contact with the flange of the first grounding plate when the cover member covers the access opening, the second grounding plate being further provided with a set of second contacts that extend into the housing via the access opening so as to establish electrical contact with the ground contacts on the circuit board when the cover member covers the access opening;
the ground contacts, the flange, and the first and second contacts cooperating to provide electromagnetic interference shielding to the electronic component.